Question

Variance of the random variable X is
(a) E(x²) – [E(x)]²
(b) [E(x)]² – E(x²)
(c) E(x²)
(d) [E(x)]²

Answer 1

Hi ,

The variance is a measure of how

spread out the value of X would be if

the experiment leading to X were

repeated a number of times .

The variance of X , written as Var( X )

is given by :

******************************************
Var( X ) = E( X² ) - [ E( X ) ]²

*******************************************

Where E( X ) is expected value of X.

Option ( a ) is correct.

I hope this helps you.

: )